Eighteen months ago Botswana became the first African country to offer antiretroviral drugs to everyone for free. A huge amount of cash has been dedicated to the cause, but money cannot buy the workers so desperately needed.

It's 5am in Gaborone and people are already queuing outside the gates of the Princess Marina Hospital.

The hospital's waiting rooms and corridors will be filled to bursting point until the doors close again at the end of the day. Staff admit they cannot treat anyone else.

This hospital is dispatching drugs and advice to more than 6,000 people, making it the largest treatment centre for HIV or Aids in the world.

Many have presumed that money - or the lack of it - has been the main obstacle to distributing the drugs that are so desperately needed. But here the crunch has come because of a lack of workers.

"We're extremely busy, every day, all the time. No matter how many patients you see the workload is unending," says Ava Avalos, one of the doctors at the hospital.

"We're in desperate need for more staff on every level: we need doctors, nurses, administrators, counsellors, social workers."

'In denial'

The problem is about to get worse as the drugs distribution programme is rolled out to new areas of the country.

If we fail I think there will be little hope for the rest of Africa

Dr Howard MoffatHospital superintendent

At the moment, Achap - a partnership between pharmaceutical giant Merck, the Bill and Melinda Gates Foundation and the Botswana government - has six treatment centres but it desperately needs to better serve rural communities.

"The skills shortage is much wider than healthcare workers. We need people who can manage the centres, do the finances and put forward budget proposals," says Achap's Brad Ryder.

There is another, sadder reason why the problem is becoming more acute. Hospital superintendent Howard Moffat confirms that many health workers have been living in denial when faced with the virus they spend their days treating - and some are being lost to Aids.

Botswana's Aids fund

Government $70m/year

Gates Foundation $10m/year

Merck Foundation $10m/year

As the so-called "death phase" of the Aids pandemic takes hold, there are casualties amongst almost all public sector workforces, including teachers, the police, and bureaucrats.

The government is desperately negotiating with China and Cuba to get more doctors, but existing staff are simultaneously being lured away by agencies in the West. Last year, Botswana lost 120 of its nurses to the UK.

Not daring to take the test

The net result is that, despite the huge amount of money being dedicated to the cause, progress is happening more slowly than had been expected.

35% of Botswana's 1.8m people are living with HIV

More than 90% do not know their status

9,000 are on treatment

14,500 are enrolled for treatment

"We thought that by offering drugs for free we would achieve more. No doubt we are saving lives, but it's not the percentage we wanted," says Ibou Thior, project director at the Harvard Aids Institute in Gaborone.

Mr Thior, alongside other experts, points to the "chronic shortage of manpower in the system", but he also blames the enormous stigma that still exists despite an extremely aggressive information campaign.

"The biggest challenge for the country is that people are not going for testing," Mr Thior says.

Explicit, eye-catching posters are everywhere - from bus stops to government buildings - likening HIV to fatal car crashes or showing boxing gloves being unable to punch through condoms.

The foreign minister says he has been instructed to highlight the fight against Aids at every public speech. And president Festus Mogae - who regularly warns that his people face extinction - himself publicly took an HIV test and declared his status (negative).

Despite this enormous effort, 90% or more of the population have still not dared to take the test.

Death sentence

"People won't agree to be tested when they think the doctor can't fix you," explains Louis Nchindo, managing director of Debswana diamond company, itself involved in trying to persuade staff to get tested.

"The philosophy is: 'If you've got a death sentence, what's the point in knowing it?'"

There are ongoing discussions about the ethics of routinely testing for HIV.

However, the real need is to combat the fear and convince people they can have a meaningful life while living with HIV.

Dr Moffat at the Princess Marina hospital says that people delay confronting the truth to such an extent that some are brought in when it's already too late.

Each day, a handful of patients will be brought into the Marina's waiting room on stretchers. Those who have waited so long are a significant drain on resources.

Pan-African implications

Up to 10 healthy patients could be given drugs and counselling during the time needed to cope with one patient in intensive care.

Fear of being tested is an enormous hurdle

As the battle goes on, the international donor community and other African countries are watching closely to assess Botswana's success.

Dr Howard Moffat is optimistic that the battle will eventually be won.

The race to train more staff is already underway, with a medical school under construction in Gaborone and almost 1,000 health care workers having been trained at the Harvard Aids Institute.

But he is also conscious of the implications for the rest of Africa if Botswana - with all the money it has in relation to a relatively small population - cannot find a way to manage the virus.

The government - one of the richest in Africa thanks to huge diamond resources - has set aside $70m a year to tackle the disease, while it has also won an unprecedented level of support from the private sector.

"We have no choice, With all the benefits that we have and all the resources that we have been given, we have to succeed," he says.

"If we fail I think there will be little hope for the rest of Africa," he warns.

Next week, BBC News Online looks at how companies are - or are not - coping with a dying workforce